“High levels” of atmospheric microplastics have been found by scientists during a year-long study at a site close to a busy northern trunk road.

Researchers from the University of Hull and Hull York Medical School took samples from the A63 in East Yorkshire to establish what particles people may be exposed to every day.

They also sampled four other sites over a two-week period, including city centre, industrial, commercial and residential locations.

The study along the A63 took place from October 2019 to October 2020, when microplastics were collected by particles deposited from the air.

They found that around 3,000 microplastics particles dropped out of the air over 24 hours, compared to an average of 1,400 microplastics particles detected in a household study last year.

Researchers found the most abundant microplastics were polyethylene from, for example, degraded plastic packaging or carrier bags; and nylon, which may be from clothes; as well as resins, which could come from degraded roads, paint marking or tyre rubber.

The study, published in the journal Atmosphere, also found microplastics of the size and shape which are inhalable by humans.

The characteristics of microplastics were largely fragment and film shapes, which are unique to degraded plastics – for example plastic bags or bottles – rather than fibres, which are more abundantly found indoors.

Lauren Jenner, lead author and postgraduate student at Hull York Medical School, said: “We found a far greater number of microplastic particles than we were expecting.

“This study underlines that microplastics are everywhere. It shows they are present in high levels in selected outdoor areas, and that the levels can be higher than indoors.

“It is vital we now investigate outdoor environments in which humans are regularly exposed to in order to find out the levels of exposure and the types of microplastics present.”

She added: “Inhalation of microplastics is an emerging cause for concern because we know from recent studies that they have been observed in human lung tissue samples.

“Plastics are designed to be durable, so they may remain inside the body for long periods without the possibility of these being broken down or removed.

“These findings can now form part of future work to help determine any health impacts, allowing us to now use representative types and realistic exposure levels of such microplastics in further cell studies.”